home bbs files messages ]

Forums before death by AOL, social media and spammers... "We can't have nice things"

   sci.electronics.design      Electronic circuit design      143,326 messages   

[   << oldest   |   < older   |   list   |   newer >   |   newest >>   ]

   Message 141,405 of 143,326   
   john larkin to All   
   Re: MMIC filter   
   29 Nov 25 21:56:58   
   
   From: jl@glen--canyon.com   
      
   On Sat, 29 Nov 2025 11:17:12 -0800, Joerg    
   wrote:   
      
   >On 11/29/25 3:38 AM, Bill Sloman wrote:   
   >> On 29/11/2025 8:56 am, Joerg wrote:   
   >>> On 11/28/25 1:32 PM, Joe Gwinn wrote:   
   >>>> On Fri, 28 Nov 2025 12:52:07 -0800, Joerg    
   >>>> wrote:   
   >>>>   
   >>>>> On 11/28/25 12:45 PM, Joerg wrote:   
   >>>   
   >>> [...]   
   >>>   
   >>>>>> To the surprise of my clients it's the contrary. The most   
   >>>>>> client-shocking redesign was an auto-align circuit for ganged   
   >>>>>> ADC-channels. High speed, high phase accuracy and all that. They   
   >>>>>> had an   
   >>>>>> elaborate time domain method with a fat DSP, lots of code and very   
   >>>>>   
   >>>>>   I meant they used a frequency domain method.   
   >>>>>   
   >>>>>> expensive chips used as programmable delay chips. The NRE alone had   
   >>>>>> been   
   >>>>>> humongous. It never reliably converged so the system hung a lot. I   
   >>>>>> suggested to ditch all that and use time domain. This caused an uproar   
   >>>>>> because I had rocked the boat a lot and usually consultants aren't   
   >>>>>> supposed to do that. "I don't think this can possibly work", "It won't   
   >>>>>> deliver the accuracy", "It won't converge either" and all that.   
   >>>>>>   
   >>>>>> Yet the boss let me do it. In the end the whole thing dropped from   
   >>>>>> three-digit dollars in HW to under 10 bucks. Instead of expensive   
   >>>>>> discrete-step time delay chips I used inductors, caps and varicap   
   >>>>>> diodes   
   >>>>>> for almost infinite granularity. The DSP became unemployed because the   
   >>>>>> connected PC could easily handle the computations. It converged in   
   >>>>>> less   
   >>>>>> than a second, always. The NRE was low because it took less than two   
   >>>>>> weeks of my time and less than a day for the programmer, and we didn't   
   >>>>>> need an expensive DSP programmer.   
   >>>>   
   >>>> Embarrassing.  Were any of the customers design team later   
   >>>> defenstrated?   
   >>>   
   >>> No, they were pretty good. It's the usual phenomenon where, in an old   
   >>> German saying, you can't see the forest because of all the trees.   
   >>   
   >> Brainstorming is designed to get around that to some extent, but if you   
   >> aren't used to thinking outside the box it's difficult to step back far   
   >> enough to get outside the box.   
   >>   
   >   
   >My experience with brainstorm sessions is not good. The results are   
   >often encouraging but then hardly anything of it gets documented and   
   >typically none of itv is implemented. All I need is a large whiteboard   
   >or a large piece of paper. Plus coffee or mate (having a mate right now).   
   >   
   >   
      
   Brainstorming is great, done right.   
      
   We sign and date our whiteboard scribbles and photograph them and   
   stash the pics in the project notes folder.   
      
   Our ideas are certainly implemented.   
      
   We had a great one last week. I designed a relay/circuit breaker   
   module and we came up with a nice way to let users gang breakers.   
      
      
   John Larkin   
   Highland Tech Glen Canyon Design Center   
   Lunatic Fringe Electronics   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)   

[   << oldest   |   < older   |   list   |   newer >   |   newest >>   ]


(c) 1994,  bbs@darkrealms.ca